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Modeling structure-dependent fracture behaviors of anisotropic cracked chevron notched Brazilian disc shale samples: Laboratory scale testing

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Theoretical and Applied Fracture Mechanics 2025年 139卷

作者： Feng, Xianhui Liu, Huilin Yin, Zhenyu Li, Tianzheng Pan, Jiliang Wang, Pei Zhai, Tianqi Li, Peng School of Resources and Safety Engineering University of Science and Technology Beijing Beijing100083 China School of Resources and Safety Engineering Central South University Hunan Changsha410083 China Department of Civil and Environmental Engineering The Hong Kong Polytechnic University Hung Hom Hong Kong Faculty of Engineering China University of Geosciences Hubei Wuhan430074 China School of Civil Engineering and Architecture East China Jiaotong University Jiangxi Nanchang330013 China China Railway Siyuan Survey and Design Group Co. Ltd. Hubei Wuhan430063 China

The anisotropic fracture behaviors of layered shales affect the exploration and development of shale gas resources. Extensive investigations have been devoted to revealing the anisotropic geomechanically behaviors of intact or flawed shale under various loading paths. However, the structure-dependent fracture behavior and fracture toughness of layered shale were not well understood. The presented studies aim to conduct static fracture mechanical testing on cracked chevron notched Brazilian disc shale samples with different bedding inclinations (θ) and different crack angles (β), to reveal the influence of layer angle and crack angle on its fracture behaviors. The mechanical properties, energy conversion, fracture toughness and macro-meson fracture characteristics are studied, as well as the applicability of the conventional and generalized fracture criterion in layered rock mass is discussed. The results show that (i) The peak loads and fracture energy both increase with the increase of θ, but they increase first and then decrease with the increase of β. (ii) All samples exhibit six different failure modes corresponding to different morphological characteristics at crack surfaces. (iii) The fracture toughness of the samples increases with the increase of θ, and the mode Ⅱ fracture toughness (KⅡC) is about twice that of the mode Ⅰ fracture toughness (KⅠC) under the same θ. The traditional maximum tangential stress (MTS) criterion predicts pure mode II fracture initiation angle (φ0Ⅱ) and KⅡC of the samples with a large error, but the generalized MTS criterion, which considers the T-stresses, has an error in predicting φ0Ⅱ, but it can accurately predict KⅡC. © 2025 Elsevier Ltd

关键词： Fracture toughness

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Determining the suitable ecological water level based on the response relationship between landscape connectivity and water level: A case study of Poyang Lake, China

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Ecological Indicators 2025年 175卷

作者： Zhang, Cheng Chen, Wenbo Huang, Fangfang School of Environmental Science and Engineering Zhejiang University of Water Resources and Electric Power Hangzhou310018 China Institute of Ecological Barrier for Coastal Zone Zhejiang University of Water Resources and Electric Power Hangzhou310018 China School of Surveying and Spatial Information Engineering East China University of Technology Nanchang330013 China Jiangxi Key Laboratory of Basin Ecological Process and Information East China University of Technology Nanchang330013 China School of Civil Engineering and Architecture Zhejiang Guangsha Vocational and Technical University of Construction Dongyang322100 China

Water level is an important indicator of hydrological regime of lake, and its spatio-temporal variation has a profound impact on habitat quality and biodiversity conservation. How to determine the suitable ecological water level has long been a hot issue in ecohydrology research. Taking Poyang Lake as a case and from the perspective of habitat, this study firstly used the range of variability approach (RVA) to analyze the natural water level regime of the lake. Then, the probability of connectivity (PC) was applied to analyze the dynamics of grassland connectivity and water connectivity after identifying the distribution pattern of grassland and water body at different water levels. Finally, the natural water level regime was corrected to the suitable ecological water level based on the response relationship between grassland connectivity, water connectivity and water level. The results showed as follows: (1) The annual variation of water level in Poyang Lake showed a significant unimodal distribution, with high water level in flood season from April to September and low water level in dry season from October to March of the following year. The annual water level can reach the highest of 22.63 m in July and the lowest of 7.12 m in February from 2000 to 2020. (2) The grassland and water body constitute the main habitats of Poyang Lake wetland. Under the disturbance of hydrological process, they presented the unique dynamic tradeoff relationships of "One shrinks while the other expands" and "One is fragmented while the other is connected", respectively. With the increase of water level, grassland connectivity decreased dramatically while water connectivity increased progressively. (3) The annual demand for suitable ecological water level is 14.82–15.65 m. In the wet season, the threshold of suitable ecological water is 14.82–16.96 m, while it is 11.75–14.82 m in the dry season. The threshold of monthly suitable ecological water level from January to December is succes

关键词： Biotic

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Chloride Ion Transmission Model under the Drying-wetting Cycles and Its Solution

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Journal of Wuhan university of technology(Materials science) 2014年第3期29卷 445-450页

作者：黄滢卫军 DONG Rongzhen ZENG Hua School of Civil Engineering Central South University College of Architecture and Civil Engineering Jiangxi Science & Technology Normal University Nation Engineering Laboratory for High Speed Railway Construction

The chloride ion transmission model considering diffusion and convection was established respectively for different zones in concrete by analyzing chloride ion transmission mechanism under the dryingwetting cycles. The finite difference method was adopted to solve the model. The equation of chloride ion transmission model in the convection and diffusion zone of concrete was discreted by the group explicit scheme with right single point （GER method） and the equation in diffusion zone was discreted by FTCS difference scheme. According to relative humidity characteristics in concrete under drying-wetting cycles, the seepage velocity equation was formulated based on Kelvin Equation and Darcy＇s Law. The time-variant equations of chloride ion concentration of concrete surface and the boundary surface of the convection and diffusion zone were established. Based on the software MATLAB the numerical calculation was carried out by using the model and basic material parameters from the experiments. The calculation of chloride ion concentration distribution in concrete is in good agreement with the drying-wetting cycles experiments. It can be shown that the chloride ion transmission model and the seepage velocity equation are reasonable and practical. Studies have shown that the chloride ion transmission in concrete considering convection and diffusion under the drying-wetting cycles is the better correlation with the actual situation than that only considering the diffusion.

关键词： under the drying-wetting cycles the chloride ion transmission model the group explicit scheme seepage velocity

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Nano-pore in C-S-H gel stability analysis of hardened cement pastes

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Key engineering Materials 2015年 645卷 335-340页

作者： Wu, Lang Xiong, Na Yu, Fangyan College of Architecture and Civil Engineering Jiangxi Science and Normal University Nanchang330013 China College of Architecture and Civil Engineering Nanchang Institute of Technology Nanchang330044 China

Based on capillary tension, surface free energy and elasticity theory, a collapse model of nano-pore in C-S-H gel was created in hardened cement pastes. The stability of pore was analyzed by Gibbs free energy theory. The results show that, the capillary is more stable while the capillary is grater and rounder in the case of the aperture changing in the nanometer scope. When the aperture is changing in the scope of micrometer, the collapse possibility of the capillary is tiny. If the capillary size is fixed, the capillary is more stable while the elastic modulus of hydrated products is higher. © (2015) Trans Tech Publications, Switzerland.

关键词： Gibbs free energy

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Influence of the source and molecular weights on sulfathiazole/sulfadiazine binding in sedimentary dissolved organic matter

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Journal of Environmental Management 2025年 386卷 125795页

作者： Yan, Caixia Zhang, Fei Nie, Minghua Luo, Yanqing Ding, Mingjun Nie, Shuhua Zhou, John L. College of Geography and Environmental Science Key Laboratory of Earth Surface Processes and Environmental Change of Tropical Islands Hainan Normal University Haikou571158 China School of Geography and Environment Key Laboratory of Poyang Lake Wetland and Watershed Research Ministry of Education Jiangxi Province Key Laboratory of Ecological Intelligent Monitoring and Comprehensive Treatment of Watershed Jiangxi Normal University 99 Ziyang Road Nanchang330022 China Jiangxi Drug Inspection Center 1566 Beijing East Road Nanchang330029 China School of Civil and Environmental Engineering University of Technology Sydney SydneyNSW 2007 Australia

Sedimental dissolved organic matter (DOM) plays a crucial role in the migration of antibiotics in a lake environment, which is strongly associated with its physicochemical properties influenced by temporal and spatial variations. This study systematically investigated the binding behavior of sulfathiazole (ST) and sulfadiazine (SD) to DOM across different molecular weights (MWs) in sediments from Poyang Lake using multiple spectroscopic techniques. Results showed that the MW fractions of DOM from the onset of the dry season were higher than those before flooding. Additionally, key carbon parameters, including dissolved organic carbon and fluorescent components, were present in greater proportion in the truly dissolved phase and the low MW fraction of DOM. These properties of the low MW fraction of DOM enhanced its binding capacity for the two sulfonamides, with the partitioning coefficient (logKcoc) values of 5.20 and 5.06 for ST and SD, respectively. Dialysis experiments investigating the interaction between different concentrations of DOM and sulfonamides indicated that humic-like and protein-like components significantly influenced the migration of ST and SD, respectively. Moreover, protein-like components exerted a more substantial impact on the migration of sulfonamides in heavily polluted sampling sites, while the humic-like substances played a more significant role for the samples from the wetland protection area. The results enhanced the understanding of the significance of DOM sources and MW in influencing the environmental fate of antibiotics in lake ecosystems. © 2025

关键词： Lake pollution

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Study on Countermeasures of Unbalanced Quotation

Study on Countermeasures of Unbalanced Quotation

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2020 International Conference on Agricultural science and technology and Food engineering, ASTFE 2020

作者： Wan, Yun Wu, Lang Civil Engineering and Architecture Jiangxi Science and Technology Normal University Nanchang Jiangxi China

This paper takes the unbalanced quotation method in the process of project bidding as the research object, analyzes its common means, causes and possible consequences. Research shows that serious unbalanced quotation will disturb the normal process of bidding. Finally, from the perspective of the owner, put forward the response strategies before bidding, in bid evaluation and in project implementation. © The Authors, published by EDP sciences, 2020.

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Probabilistic assessment of response spectra for multiple damping levels in seismic hazard analysis

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Soil Dynamics and Earthquake engineering 2025年 196卷

作者： Zhang, Haizhong Zhang, Rui Zhao, Yan-Gang Si, Hongjun Zhang, Haixiu Eco-Science Course Faculty of Agriculture Yamagata University 1-23 Wakaba-machi Yamagata Tsuruoka-shi997-8555 Japan School of Geography and Tourism Qilu Normal University Jinan250200 China Faculty of Architecture Civil and Transportation Engineering Beijing University of Technology Beijing100124 China Seismological Research Institute Inc. Tokyo Japan Luanping County Branch of Chengde Ecological Environment Bureau Chengde China

The response spectra for specific recurrence periods are typically constructed for a 5 % damping ratio based on probabilistic seismic hazard analysis (PSHA). Nevertheless, practical structures exhibit a range of damping characteristics, requiring response spectra at various damping levels. Commonly, a damping modification factor (DMF) is applied to adjust the 5 %-damped spectra derived from PSHA to other damping levels. Most DMF formulations, however, are developed solely through the regression analysis of seismic records, overlooking the consistency of the recurrence period of the response spectra before and after adjustment. A direct probabilistic analysis of the response spectra across different damping ratios provides a more reasonable solution, although it typically needs multiple ground motion prediction equations (GMPEs) for each damping level or, alternatively, the application of a DMF to adjust the 5 %-damped GMPE. However, many recent studies have highlighted the difficulty of directly constraining the scaling of the response spectra within GMPEs via seismological theory. To address this issue, this study proposes a new framework for conducting a probabilistic analysis of the response spectra across multiple damping ratios. The framework estimates site-specific response spectra for various damping ratios using a single GMPE for the Fourier amplitude spectrum (FAS) combined with a ground-motion duration model. Because the FAS is more closely related to the physics of wave propagation, its scaling within GMPEs is easier to constrain using seismological theory. Furthermore, the moment method, in conjunction with Latin hypercube sampling, is applied to calculate the exceedance probability for response spectra with any damping ratio, thereby obtaining the corresponding seismic hazard curves. The proposed framework was verified and compared with traditional approaches using a numerical example. The proposed framework enables the acquisition of response spectra f

关键词： Damping

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Mechanical properties and dynamic constitutive model of concrete after freeze-thaw under impact load

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Journal of Building engineering 2025年 108卷

作者： Wu, Qianyun Ma, Qinyong Duan, Xuelei Su, Danyang Fuyang Normal University Anhui Fuyang236041 China School of Civil Engineering and Architecture Anhui University of Science and Technology Huainan232001 China CAS Key Laboratory for Mechanical Behavior and Design of Materials Department of Modern Mechanics University of Science and Technology of China Anhui Hefei230027 China Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering Hohai University Jiangsu Nanjing China School of Management Suzhou University Anhui Suzhou234000 China

To investigate the mechanical properties and energy evolution of freeze–thawed concrete under both static and dynamic loading, static compression and dynamic impact tests were conducted. The resulting data included stress–strain curves, strength and deformation parameters, crushing characteristics, and energy evolution patterns of freeze-thawed concrete under these conditions. A dynamic constitutive model incorporating strain rate and temperature-induced damage was developed using the Zhu-Wang-Tang (Z-W-T) nonlinear viscoelastic model. The findings indicated that the static compressive strength, peak strain, and longitudinal wave velocity of the concrete decreased with decreasing freezing temperature, while the mass loss and damage increased. Under static uniaxial compression, the total input energy (U), elastic strain energy (Ue), and dissipated energy (Ud) all decreased as the temperature dropped. The stress-strain curve of C40 concrete exhibited a rapid decline after the peak, whereas that of C60 concrete exhibited a more gradual post-peak descent. At a constant temperature, the dynamic peak stress, dynamic peak strain, and dynamic deformation modulus of the freeze-thawed concrete increased with increasing strain rates. Notably, lower temperatures corresponded to higher impact toughness indices after freeze-thaw cycles. Furthermore, higher concrete strength grades resulted in greater impact toughness indices after freezing and thawing. In the impact compression tests, increased strain rates led to more severe fragmentation, smaller average block sizes, and higher fractal dimensions. The proposed dynamic constitutive model accounted for both strain rate and temperature damage and was validated by comparing the experimental results with theoretical predictions. This comparison confirmed the accuracy and applicability of describing the dynamic strength and deformation behavior of freeze–thawed concrete under impact loading. © 2025 Elsevier Ltd

关键词： Strain rate

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Research on Protection and Utilization Strategies of cultural Resources in Traditional Villages of Tourism Development 3

Research on Protection and Utilization Strategies of cultura...

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3rd International Conference on Energy Resources and Sustainable Development, ICERSD 2020

作者： Luo, Yiqing Wang, Donghua Wen, Haiqiao Civil Engineering and Architecture Jiangxi Science and Technology Normal University Nanchang Jiangxi330013 China

Pailou Village which is the hometown of Song Yingxing, who is the author of Tien-kung K'ai-wu, is taken as the research object in this paper. From the perspective of tourism development of traditional villages, the types of cultural resources in Pailou Village are summarized through combing the content of existing cultural resources. Then the value of its cultural resources is analyzed from three aspects: history and culture, art and society, tourism and economy. Therefore, the development path of the integration of culture and tourism is proposed, from five aspects of project positioning, industrial format, tourism planning, supporting facilities and smart tourism, the strategy of improving the tourism competitiveness of Pailou Village are summarized in this paper, which provides a theoretical reference for the sustainable development of traditional village tourism. © The Authors, published by EDP sciences 2021.

关键词： History

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Discussion on blasting vibration monitoring for rock damage control in rock slope excavation

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Earthquake engineering and engineering Vibration 2022年第1期21卷 53-65页

作者： Yang Jianhua Cai Jiyong Yao Chi Zhang Xiaobo Liu Liansheng School of Civil Engineering and Architecture Nanchang UniversityNanchang 30031China School of Resource and Environmental Engineering Jiangxi University of Science and TechnologyGanzhou 341000China

Drill and blast is a commonly used method for rock slope excavation in hydropower *** blasting excavation of rock slopes,far-field vibration monitoring on the first upper berm for statutory compliance is usually performed to control the blast-induced rock damage to the final slope *** this study,for the rock slope excavation in the Jinping-I hydropower station,the field vibration monitoring and acoustic testing are presented to investigate the vibration characteristics on the first upper berm and the damage depth in the current *** relationship between the PPV on the first upper berm and the PPV damage threshold on the damage zone boundary is also studied through three-dimensional FEM *** results show that on the first upper berm,the maximum vibration velocity component occurs in the vertical *** on the blasting damage zone boundary,the horizontal radial vibration velocity is the maximum *** the Jinping-I slope with a bench height of 30 m,the radial PPV on the inner side of the first upper berm is 2.06%of the PPV threshold on the damage zone *** ratio is increased as the bench height ***,the bench height of the rock slope is an important factor that cannot be ignored in determining the allowable vibration velocity for rock damage control.

关键词： rock slope blasting excavation vibration rock damage

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